Magnetic chuck



Nov. 11, 1924- 1,515,288

H. E. TRACY MAGNETIC CHUCK Filed March 4, 1922 5 Sheets-Sheet 1 jfoward E. Twig H. E. TRACY MAGNETIC CHUCK Nov. 11, 1924- s Sheets-Shet 2 Filed March 4, 1922 H. E. TRACY MAGNETIC CHUCK Nov. 11 1924- Filed March 4, 1922 5 Sheets-Sheet 5 Irwenior: howard E. T

Patented Nov. 11, 1924.

Application filed To all 10710222 it mcg conc n 4--- L Ur n huseecs.

Vorcester. in the coun Commonwealth of his vented a new a l1(l useful Magnetic t huck, of which the 'tollowi 7 gl'other with the accompanying drav-fin specification.

My invention relates and has particular refer viding work holdinp' large number of sepals 3 son of which it is peculiarly the retention of thin work.

The object of my invention to provide an improvec arrangement and cons uiction of the parts of a magnetic chuck ot' the above described type that is extremely effective and durable in use and is highly desirable from a manufacturing standpoint.

In United States Patent No. 1,329.?33, issued February 3. 1.920.. to U. Walker, there is shown and described a magnetic chuck in which the work holding face consists of a number of separately magnetized polar sections. each section presenting a plurality of independentfiush projections. The several polar sections are arranged within an inclosing; frame and held in position therein by insulating material, which also fills the gaps between adjacent polar projections and thus forms. in effect, an integral work holding face. lVhile a chuck constructed as described above. is extremely effective in operation, it has been found that with the rough handling which the chucks receive from the average workman, the polar sections are liable to be broken loose from the frame. owing to the fact that it is difficult to tind an insulating material possessing an; great mechanical strength.

According to the present invention. propose to provide an improved magnetic chuck embodying the same general principles of construction as set forth in the a cove described patent, but also possessing great mechanical strength. My invention contemplates an improved arrangement of the parts in which a portion of the polar projections are formed integral with the frame, while the remaining polar projections are so formed as to permit their being readily ring ot the insulatinc fu'thcr contemed construction in which 4 are magnetized by the nnheu of energizi g l here .ter aopearxre. the accompanyin;- drawiew of a chuck em sectional view along l 5 ierse sectional view along the line 5-0, Fig. 1.

F n 6 is a bottom plan view of the face plate, showing one-half thereof completed and the other half in process ct manufacu is a top plan view of the frame of bllG face plate shown in Fig. 1.

i 8 is a transverse sectional view along line 808, Fig. 7.

p 9 is a fragmentary sectional view 0 57' the line 9 9, Fig. 7.

Bios. 10 a. d 11 are views in perspective. showing the form of the polar projections which are inserted in the frame shown in Fig. 7.

12 is a diagrammath view showing the relation between the polar projections shown in Figs. 10 and 11, when assembled.

Like refe'ence characters refer to like parts in the different figures.

Referring to Figs. 1 and 2-. the chuck generally comprises a work holding fa :e plate 1. mounted upon a body which. as best shownin Fig. at, provided with backplate seat for the eception of backolate. not shown. by means of which the chuck insulating plate 13 secured to the body 2. The coils 9 and are so wound that when they are energized, the hub 6 and the out side flange 8 will be of one polarity, while the inner flange 7 will be of the opposite polarity, as indicated,- the purpose of which arrangement will hereinafter more fully appear. V

Referring now to Figs. 7, 8 and 9, the face plate 1 consists of a casting or forging generally circular inform, and providing a central hub portion 1 1 from which radiate arms connected by an annular rim 16, the arms 15 beingundercut with respect to the hub 1e and the rim 16, as indicated at 17, so that when the plate 1 is secured to the body 2, only the nub 1 and the rim 16 will be in engagement with the hub 6 and the outer flange 8 respectively, of the body for a purpose to be hereinafter described. The upper surface of each arm 15 is provided with a series of spaced projections 18 extending in opposite directions and in staggered relation from the center line of the arm into the spaces between adjacent arms, the projections 18 being flush with the top of the hub 1 1 and the rim 16. V

The top of the face plate 1 thus presents a plurality of concentric series of spaced projections, as shown in Fig. '4', while the under side thereof presents a plurality of segmental shaped spaces 19, best shown in Fig. 6. The spaces 19 are each adapted to receive a pair of polar sections 20 and 21, each section being spaced apart from the other and from the sides of the spaces 19. As best shown in Fig. 10, the section 20 con sists of a segmental portion 22, upon which is formed a. plurality of upwardly and laterally extending projections 23. As best shown in Fig. 11, the section 21 similarly consists of a segmental portion 24: provided with upwardly and laterally extending pro jections The projections 23 and are so arranged with respect to each other that when the sections 20 and 21 are placed side by side, as indicated in Fig. 12, the pr0jections 23 and 25 extend in tions in staggered relation. From a comparison of Figs. 7 and 12, it is apparent that the projections 23 and 25 are spaced apart from each other substantially the same distance as the projections 18.

Having thus described the various parts entering into the construction of my improved chuck, the method of assembling same will now be described. The face plate 1, constructed as shown in Fig. 7, is first placed upon a suitable flat surface with the projections 18 in contact with same. A pair of sections 20 and 21 are then inserted in each of the spaces 19, with the projections 23 interlockingwith and spaced from the projections 18 of the arm 15 on one side of the space 19, and with the projections 25 interopposite direclocking with and spaced from the projections 18 of the arm, on the other side of the same space. The opposed straight edges of each pair sections 20 and 21 are separated by a space, indicated at 26. A pair of sections 20 and 21 having been arranged in each of the spaces 19, as shown at the right in Fig. 6, a non-magnetic insulating material, in a plastic condition, is poured into each or" the spaces 19 until'it completely, fills the gaps between the projections 18, 23 and 5 and be ween the segmental portions 22 r d 2 1- of the sections 20 and 21, after which The top or" the fa e plate 1 then presents the appearance s iown in Fig. 1 with the several polar projections 18, 23 and 25, each sep arated from the other by the insulating ma- 611211, all of the projections being flush with he hui 1 and the rim 16 of the plate, to

smooth flat surface. The underas of insulating material is allowed to harden.

tie p ate '1 then appears as shown at he 1 ft in Fig. 6, each pair of sections 20 and being embedded in the insulating material within the openings 19, with only the raised. seats 22 and 24 provided on the.

segmental portions 22 and '24: flush with the surface of the insulating material.

The plate 1, after machining as a unit, is

then secured to the body 2 by means of the screws 5 which hold the hub 14 and the run 16 in close enga 'ement with the hub 6 and the flange 8 respectively, as described above,

present a plurality of concentrically aiid'radially arranged polar projections in which each projection of ne polarity is substantially surrounded by projections of the opposite polari as indicated in Fig. 1.

From the foregoing it'is apparent that l have provided an improved magnetic chuck in which the work holding face consists of a large number of separate polar projections forming; a substantially unitary structure possessing eat mechanical strength. The

strength of the work holding face results 7 from the fact that one-half of the separate polar projections, as well as the central hub 1 1 and the outer rim 16 are formed in one piece, so that almost any piece of work, no matter how small or thin, is always rigidly supported by at least one or more of the polar projections 18. Furthermore, the projections 23 and of the polar sections 20 and 21 are so interlocked with the arms 15 of the face plate, that the possibility of any of the projections 23 or 25 being broken chuck is well adapted to away from the face plate, is reduced to a minimum, Consequently my improved stand up under most any amount of rough handling to which it may be subjected, by reason of careless workmen dropping pieces of material thereon.

My improved face plate construction is also believed to be particularly advantageous in view of the fact that it permits of the several sets of polar projections being independently magnetized by the use of only two concentric coils arranged between the flanges and hub of the base plate. This arrangement materially reouces the cost of manufacture and eliminates complicated electrical connections which would be not essay for additional coils, as shown in the above mentioned Patent No. 1,329,733. WVhile the above described embodiment of my invention shows a chuck employing but two concentric coils, it will be obvious that this same type of construction is applicable to chucks in which coils'in multiples of two are employed, the annular flanges between the hub portion and the outer flange of he body being increased in number as desired.

lVhile I have shown my invention in its simplest and preferred form, and as being embodied in a circular chuck, it is not so limited, but may as well be embodied in chucks of different forms and shapes, wit out departing from the spirit and scope of my invention. I desire, therefore, that only such limitations be imposed thereon as come within the scope of the appended claims.

I claim,

1. In a magnetic chuck, a work-holding face plate, consisting of a frame providing a plurality of independent spaced flush surfaces arranged in rows in staggered relation and a plurality of polar sections, each providing independent spaced flush surfaces in terposed between those of said frame.

2. In a magnetic chuck, a work-holding face plate, consisting of a frame providing a plurality of independent spaced flush surfaces arranged in rows in staggered relation and a plurality of polar sections, each providing independent spaced flush surfaces interposed between those of the said frame. the surfaces of said frame and of said sections being of opposite polarity.

3. In a magnetic chuck, work-holding face plate, consisting of a plurality of rows of magnetized flush surfaces, each surface being of opposite polarity from the adja cent surfaces of its row and from the corresponding surfaces in adjacent rows. the surfaces of one polarity being magnetized from a unitary frame.

4. In a magnetic chuck, a work-holding face plate, consisting of a plurality of rows of magnetized flush surfaces, each surface being of opposite polarity from the adjacent face plate, consisting of a frame providing a plurality of openings into each of which extend than, spaced projections arranged in relation and a plurality of pole ions receivable in said openings and provic ng flush spaced projections interposed :etween the projections on said frame.

3. In a magnetic chuck, a work-holding face plate. consisting of a frame providing a plurality of openings into each of which extend flush spaced projections arranged in ered relation and a plurality of polar one receivable in said openings and prong flush spaced projections interposed en the projections on said frame, the me on said frame and on said secc.ng of opposite polarity.

' plate, consisting of a frame providing plurality of openings into each of which E nd fiush spaced projections arranged in staggered relation and a plurality of polar sect-ions receivable in said openings and proriding flush spaced projections interposed between the projections on said frame, the spaces between said projections being filled with non-magnetic material to provide an integral face.

8. In a magnetic chuck, a work-holding face plate, consisting of a frame providing a ilurality of openings into each of which extend flush spaced projections from opposite sides and a plurality of polar sections receivable in said openings and providing flush spaced projections interposed between the projections on said frame. the said polar sections being embedded in non-magnetic material wi in said frame, whereby said flush projections provide a smooth workholding face.

9. In a magnetic chuck, a work-holding face plate, consisting of a frame providing a plurality of openings into each of which extend flush spaced projections from opposit-e sides and plurality of polar sections receivable in said openin 's and providing flush spaced projections imvrposed between the projections onsaid frame, the spaces between said projections being filled with non-magnetic material and the said polar sections being embedded in non-magnetic material within said frame to provide an integral structure.

10. In a magnetic chuck, a work-holding face plate, consisting of a frame providing a plurality of openings into each of which extend flush spaced projections from opposite sides and a plurality of polar sections In a magnetic chuck, a work-holding face plate, consisting of a frame providing a central hub with arms radiating therefrom and each carrying'spaced flush projections arranged in staggered relation and a plurality of polar sections receivable in the spaces between said arms and each providing spaced flush projections, arranged in sta 'ered relation and inter )osed between and means for the projections on said arms, imparting opposite magnetic projections carried by said sections, respectively.

polarity to the a work holding arms and said 13. In a magnetic chuck, a worlcholding face plate, consisting of a frame providing a central hub with arms radiating therein and each carrying spaced flush proplnra-lity of poiar sections receivable. in the spaces between said arms and each providing spaced flush. projections interposed between the means for imparting opposite magnetic polarity to the hub'of said frame and to the said polar sections. a

1 In a magnetic chuck, a work-holding face plate. consisting of frame providing projections on saidarms, and

l! -1 jections on opposite sides thereof and a a central hub with arms radiating therefrom and each carrying spaced fiush projections arranged in staggered relation and a plurality of polar sections receivable in the spaces 1 etwecn said arms and each pro-.

viding spaced flush project-ions arranged in staggered relation and interposed between the pro ections on said arms, the spaces between said pro irith non-magnetic material.

Dated this 28th day of February, 1922.

HOTVARD E. TRACY.

ections and betweensaid i polar sections and sald arms being filled 

